In local area networks, when a node joins the network, the first stream of signals it receives are connection management symbols. The symbols are especially chosen so that they can be decoded by an encoder/decoder (ENDEC) of the node without regard to their alignment within a byte of the signal stream. In a standard 4-bit/5-bit encoding scheme, the start of the connection management symbols can be at any one of the 10 bits within the "byte". Decoding of these connection management symbols precedes without regard to this alignment because of their chosen nature. However, once these symbols are processed, decoding of the data packet following these symbols requires that their "bytes" be aligned.
Typically, the required alignment was provided by the detection of a packet delimiter called a "JK" symbol/pair. Under this procedure, a preamble "byte" immediately preceding the "JK" symbol-pair could be misinterpreted, being an incorrectly decoded byte.
Also because of the manner in which an elastic buffer, used in a typical ENDEC, is reset upon detection of the "JK" delimiter and then initialized, a few bits in the byte-stream are dropped, resulting in a non-integral number of bytes in the preamble.
Furthermore, a typical ENDEC generated a SMASH signal whenever a JK symbol-pair is detected which differs in synchronization from that currently in effect.